Cylinder lock-key-combination

Abstract: A disc cylinder lock - key - combination, comprises a cylinder housing (1) and inside thereof, a turnable inner cylinder (2) enclosing a stack of discs including a number of locking discs (3, 4). The locking discs (3, 4) are turnable by means of the key (12) of the lock into a releasing position of the lock mechanism. The key opening (6, 7) of the locking discs (3, 4) is so formed that it comprises at least one internal protrusion (21) narrowing a part of the key opening (6, 7). The adjacent sides of the protrusion (21) can be substantially perpendicular with respect to each other. One side of the protrusion (21) forms a combination surface (22) arranged to cooperate with a corresponding combination surface (27) in the key (12) for determining the turning movement of a locking disc (3, 4) to open the lock and the other side of the protrusion (21) forms a return surface (23) for the locking disc (3, 4) on which the key (12) acts by means of a guiding element (14) when returning a locking disc (3, 4) into its locked position.

Description: The invention relates to a cylinder lock - key - combination in accordance with the preamble of claim 1 or claim 11 and to a key or a key blank provided therefor. A cylinder lock of a kind provided with turnable locking discs has been known as such for a long time. Even though the number of different opening combinations available in this lock type is enormous, there has been a need to create further different opening variations so as to avoid coincidences, i.e. a key opens by chance a lock it is not supposed to, which is very rare as such, but especially to be able to provide lock groups for separate clients including a large number of locks and keys possibly arranged hierarchically as mastered locking systems. One solution is to increase the number of the locking discs in the lock. However, unless the discs are made unacceptably thin a consequence of this solution is that the lock needs more space in the axial direction thereof to accommodate it and, thus, in practice, the lock is no longer applicable for insetting in doors or objects to be locked which are of conventional thickness. Therefore, a more advantageous alternative solution is to provide a range of different new key profiles, which are at least partly, and preferably entirely, mutually incompatible. A prior art solution of providing new key profiles is disclosed in the patent publication FI-A-68290 (corresponding to US-A-4127996). Conventionally this prior art lock type has been operated by a key, the basic profile of which is semicircular in the cross-sectional plane of the key shaft. Therefore, due to manufacturing techniques, the possibilities to provide new mutually incompatible profile variations are in practice, however, rather limited. As key shafts having basically a semicircular profile have been in general use for many years, the key security relating thereto or to key profiles derived therefrom continually gets more risky, because by cutting additional grooves in the key profiles of keys already in use, they can be made compatible or operable also with locks intended only for the new key profiles. A further known key shaft profile utilized in the lock type in question has a somewhat rectangular cross-section, This version, however, relates to a specific bidirectionally operable cylinder lock provided with turnable locking discs, cf. for instance FI-A-74320 (corresponding to US-A-4351172 and forming the basis of the preamble of claim 9). In this known arrangement, returning of the locking discs takes place by means of one or more return bars movable at the periphery thereof and to which force transmission from the key is accomplished through a so-called lifting O-locking disc. Relating further to this lock version, FI-A-81429 (corresponding to US-A-4686843 and forming the basis of the preamble of claims 1 and 11) discloses a separate guiding element inserted in the key channel, the purpose of which is, together with rotation limiting means, to prevent inadvertent scrambling of the stack of locking discs by guiding insertion of the key into the lock and its removal from the lock so that axial displacement of the key relative to the stack of discs can take place only in a certain angular position of the discs in the lock cylinder. A further purpose for the prior art guiding element is to impede picking of the lock. In addition, by varying the form of the guiding element, new key profiles can be provided. In this prior art arrangement the guiding element, however, never acts directly on the locking discs themselves. WO 89/11014 discloses a further solution based on the conventional semicircular key shaft profile and in which the combination surfaces as well as the return surfaces, provided for returning of the locking discs, are located conventionally on the plane side of the key shaft. In addition, this arrangement includes two bars attached to the lifting O-locking disc, of which one bar is located in the key channel itself. These bars together return the locking discs when the key is turned back towards the locked position of the lock mechanism. The purpose of this known arrangement is also to prevent picking of the lock by preventing probing and displacement of individual locking discs by means of a picklock. Otherwise returning of the locking discs takes place, in normal use of the lock mechanism, by means of the key in a wholly conventional manner. One aim of the invention is to provide new profile variations for the basic lock type referred to above, operable in one direction and provided with turnable locking discs, by means of a new solution, in which a guiding element, known as such, and located in the key channel is utilised so that the advantages of the prior art solutions are retained but at least some of the disadvantages thereof are avoided. At the same time a further aim of the invention is to provide some new key shaft profiles, by means of which key security pertaining to this basic lock type can be further improved. The aims of the invention are achieved with the disc cylinder lock - key - combination defined in the following claim 1 or the disc cylinder-key-combination defined in the following claim 11. Thus, by utilising a new kind of combination of the key opening of a locking disc, and of the key profile and a returning of the locking discs by means of a guiding element located in the key channel, a new basic profile and new surfaces therein can be made available for providing novel profile variations of the key shaft and thus an increased number of possible opening combinations. The extent of the return surface in a modified locking disc need not be as large as that of a combination surface. Therefore in practice it is possible for the length of the return surface in the key opening of the at least one locking disc to be less than a third of the length of the combination surface of the locking disc. Thus, more space is available on the key shaft for surfaces that can be used for profile variations. The key opening of a modified locking disc is, with advantage, designed so that it includes a curved surface extending from one end of the return surface, the curved surface being located at the radial position occupied by the possible locations for the peripheral notches in the locking disc, said curved surface being formed and positioned so that the minimum distance between a cut peripheral notch and the key opening is preferably at least 1 mm. In this way it is ensured that the region between the peripheral notches and the key opening remains sufficiently wide to provide the necessary strength for each modified locking disc. The guiding element preferably comprises two members extending symmetrically on opposite sides of the key channel in the axial direction thereof, whereby the key opening of each locking disc comprises, correspondingly, two separate internal protrusions each including a return surface arranged to cooperate with a respective one of the axial members of the guiding element. In this way it is ensured that the key can be inserted in the key channel in two separate positions spaced 180° apart. In practice an advantageous embodiment is achieved if a profile disc, turnable with the key of the lock and acting to limit the shape of the key channel, is arranged between the cylinder housing and the inner cylinder at the end where the key is first inserted, whereby the guiding element is supported by this profile disc. The key opening of che profile disc can then be systematically varied to provide one of a range of possible different lock-key-families based on different profiles of key shaft. In order to increase the number of possible profile variations and to provide an improved support for the guiding element, the latter is conveniently supported by a lifting O-locking disc, arranged along the key channel towards the inner part of the inner cylinder, whereby the key opening of said lifting O-locking disc can be varied independently of said profile disc for further defining the key profile of the key shaft at its end first inserted into the lock. The invention also provides a key or a key blank according to claim 9. In this way the compatibility of the key with the lock is secured and at the same time it is possible to improve key security by preventing the use of keys with somewhat similar profiles in the lock in question. In addition, the key conveniently comprises two series of combination surfaces located symmetrically on opposite sides of the centre axis of the shaft part of the key, whereby the edges of the shaft part of the key located adjacent to said series of combination surfaces are rounded. In this way the key can be inserted in the lock in two different turning positions as described above and the lock can be opened from either of these positions, which is convenient for the user. If, however, the key includes only one series of combination surfaces, more possibilities are achieved for profile variations, but at the expense of the convenience of two-sided operation. The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an exploded view of one embodiment of a cylinder lock - key - combination according to the invention, Figure 2 shows a normal locking disc included in the combination of Figure 1, Figure 3 shows a profile disc to be utilised in a lock - key - combination accordingly to the invention, and in addition some possible profile variation arrangements illustrated by dotted lines, Figure 4 shows a lifting O-locking disc to be utilised in a lock - key - combination according to the invention, and in addition some possible profile variation arrangements illustrated by dotted lines, Figure 5 is a cross-sectional view of the basic profile of a key shaft in the combination according to the invention showing also the possible combination cuts, Figure 6a is a cross-sectional view of the profile of the key shaft at the position corresponding to the profile disc of Figure 3, and Figure 6b is a cross-sectional view of the profile of the key shaft at the position corresponding to the lifting O-locking disc of Figure 4. In the drawings, 1 indicates a cylinder housing having a turnable inner cylinder 2 located therein. The inner cylinder 2 encloses a stack of discs, which includes a number of normal locking discs 4 turnable with a key 12 of the lock and having a key opening 7 and a peripheral notch 20 determining the opening combination of the lock mechanism, and at least one lifting O-locking disc 3 having a key opening 6. The locking discs 4 are separated from each other by means of intermediate discs 5 having a key opening 8. The lock mechanism also includes a locking bar 10, which, in the locked position of the lock mechanism, is located partly in a groove 30 in the cylinder housing 1 and partly in a slot 9 in the inner cylinder, thereby preventing turning of the inner cylinder 2 with regard to the cylinder housing 1. The locking discs 4 can each be turned with the key 12 of the lock into a position, in which the respective peripheral notches 20 line up to form, at the position of the slot 9 of the inner cylinder 2 in the axial direction of the lock, a uniform channel, into which the locking bar 10 can enter from the groove 30 in the cylinder housing 1 thereby releasing the inner cylinder 2 to turn, together with the key, with regard to the cylinder housing 1. This turning movement of the inner cylinder 2 represents unlocking of the lock and is transmitted to some further member, for instance to a lock bolt (not shown). In Figure 1, 13 indicates generally the means by which the inner cylinder 2, with its stack of discs, is axially locked to the cylinder housing 1 and by means of which force transmission from the inner cylinder 2 to the further member can take place. As is generally known, this type of lock mechanism operates under positive guidance, whereby the lifting O-locking disc 3 is arranged to press the locking bar 10 back into the groove 30 in the cylinder housing 1 when the lock mechanism is relocked. In this connection, a spring 11 is used for assisting this movement of the locking bar 10 and thus for making the operation smoother. The lock also includes a guiding element 14 located in the key channel formed jointly by the key openings 6, 7 and 8 in the discs 3, 4 and 5 of the stack of discs. In the embodiment of Figure 1, the guiding element 14 comprises two straight members extending axially on opposite sides of the key channel within the stack of discs, these straight members being connected together at the inner end of the key channel. The shaft of the key 12, respectively, has two grooves 25 formed therein, each groove being sized and positioned to accommodate a respective one of the straight members of the guiding element 14. As shown in Figure 1, the guiding element 14 is supported at the inner end of the inner cylinder 2 by the lifting O-locking disc 3 and at the outer end thereof (i.e. near the inlet end of the key passage) by a profile disc 15. Both of the discs 3 and 15 turn continuously with the key, when the key is turned in the lock, whereby return of the locking discs 4 is carried out unconventionally by means of the groove 25 of the key, the discs 3 and 15 and the guiding element 14 linking them so that the guiding element 14 acts on a counter surface 23 formed as part of the key opening 7 of each locking disc 4 (cf. Figure 2). The lock of Figure 1 also includes a drill-resisting member 19 and limiting members 16 and 17 which are advantageous from the viewpoint of reliable operation of the lock, by allowing insertion of the key 12 into the lock and removal thereof only in one position of the stack of discs. Thus the members 16, 17 prevent inadvertent scrambling of the stack of discs, and together with the guiding element 14 they reduce wear on the lock mechanism caused especially by insertion and removal movements of the key when the lock is operated. In practice, said limitation can be arranged through different means. In the illustrated arrangement limiting plates 17a and 17b are supported within a sleeve 16, which, in turn, is supported so that it does not turn relative to the inner cylinder 2. When the key 12 is turned in the lock, the limiting plates 17a and 17b move radially towards the shaft of the key 12 and internal projections in the plates 17a, 17b move into recesses 31 formed in the key shaft to prevent removal of the key from the lock until the key is turned back to its initial position corresponding to the insertion position. A plate 18 supports the limiting members 16 and 17 from inside of the lock. Figure 2 shows a modified locking disc 4 included in the lock. The key opening 7 of the locking disc 4 has two symmetrically arranged internal protrusions or steps 21, which include combination surfaces 22, designed to cooperate with combination surfaces 27 to be cut in the key (cf. Figure 5), and return surfaces 23, which, when the key is returned to the initial insertion position after an unlocking operation of the lock mechanism, under the influence of the guiding element 14 cause a turning of the locking discs 4 back to their initial position corresponding to the locked position of the lock mechanism as described above. The key opening 7 in each disc 4 also has a curved surface 24, which is formed so that the minimum distance A between the key opening 7 and the peripheral notches 20 is sufficient having regard to manufacturing techniques and strength requirements for the disc. The distance A is preferably at least 1 mm. Figure 3 shows a profile disc 15 to be utilised in a lock according to the invention with a key opening 32. The opening 32 is made use of to provide further possible profile variations in the key shaft, some of which variations are shown with dotted lines in Figure 3. Thus the need for long profile grooves extending over the whole length of the shaft of the key is determined by the shape of the opening 32 in the profile disc 15. In addition, the need for short grooves in the key shaft will be determined by the shape of the key opening 6 in the lifting O-locking disc 3 in a way known per se , as is shown in Figure 4. The profile of the key shaft required to correspond to the profile disc 15 according to Figure 3 and to the O-locking disc 3 according to Figure 4 is shown in Figures 6a and 6b. In the embodiment of Figure 1, the lifting O-locking disc 3 is the innermost disc in the stack of discs in the inner cylinder 2. This is not necessary from a viewpoint of the operation of the lock mechanism, and when desired the lifting O-locking disc 3 can be moved outwardly in the stack of discs towards the inlet end of the stack and, if this is done, longer profile grooves will have to be provided in the key shaft when further possible profile variations are to be used. Naturally the form and size of the long or short profile grooves can be varied widely according to need. As is especially apparent from Figure 5, the key can, with advantage, be provided with two series of combination surfaces 27, the cutting of each of which is started from a rather acute corner 26 and a side 33 in association therewith, so as to secure a sufficiently effective surface for the combination surface. The corner 28 adjacent to each corner 26 is rounded to take account of the requirements for the design of the key opening 7 as discussed above with reference to Figure 2. At the same time it should be observed that the combination surface 27 to be cut in the key shaft can be made sufficiently long so as to secure a reliable operation of the lock mechanism. The invention is not limited to the embodiment illustrated since several modifications thereto are feasible within the scope of the following claims.

Claims: A disc cylinder lock - key - combination, comprising a cylinder housing (1) and inside thereof, a turnable inner cylinder (2) enclosing a stack of discs including a number of locking discs (3, 4) operating by their periphery, each provided with at least one peripheral notch (20) engageable in a releasing position of the lock mechanism by a locking bar (10), which in its locking position prevents turning of the inner cylinder (2) with regard to the cylinder housing (1), whereby the locking discs (3, 4) are turnable by means of the key (12) of the lock into a releasing position of the lock mechanism, and a guiding element (14) in a key channel formed jointly by key openings (6, 7) of the discs (3, 4) included in the stack of discs, extending longitudinally over the stack of discs and arranged to guidingly engage with a groove (25) of the key shaft (12) during its insertion into the lock so as to turn after insertion continuously with the key (12) when the key is turned in the lock, the stack of discs including a number of locking discs (3, 4), the key opening (6, 7) of at least one of which is formed with at least one internal protrusion (21) extending into a part of the key opening (6, 7), wherein one side of the protrusion (21) forms a combination surface (22) arranged to cooperate with a corresponding combination surface (27) of the key shaft (12) for determining the turning movement of the at least one locking disc (3, 4) relative to the inner cylinder (2) when the key (12) is turned in the opening direction of the lock mechanism to secure opening of the lock mechanism, characterised in that the other side of the protrusion (21) respectively forms a return surface (23) for the at least one locking disc (3, 4) on which the key shaft (12) is arranged to act by means of the guiding element (14) for returning the at least one locking disc (3, 4) into a locking position of the lock mechanism corresponding to a position allowing initial insertion of the key (12). A combination according to claim 1, characterised in that the internal protrusion (21) provides adjacent sides in the key opening which are substantially perpendicular. A combination according to claim 1 or claim 2, characterised in that the return surface (23) in the key opening of the at least one locking disc is essentially shorter than the combination surface (22) of the at least one locking disc. A combination according to claim 3, characterised in that the return surface (23) is less than a third of the length of the combination surface (22). A combination according to any one preceding claim, characterised in that the key opening (7) of the at least one locking disc (4) includes a curved surface (24) extending from one end of the return surface (23), the curved surface (24) being located at the radial position occupied by the possible locations for the peripheral notches (20) in the locking disc (4), said curved surface (24) being formed and positioned so that the minimum distance (A) between a cut peripheral notch (20) and the key opening (7) is at least 1 mm. A combination according to any one of the preceding claims, characterised in that said guiding element (14) comprises two members extending symmetrically on opposite sides of the key channel in the axial direction thereof and in that the key opening (6, 7) of the at least one locking disc comprises, correspondingly, two separate internal protrusions (21) each including a return surface (23) arranged to cooperate with a respective one of the axial members of the guiding element (14). A combination according to any one of the preceding claims, characterised in that a profile disc (15) turnable with the key (12) of the lock and acting to limit the shape of the key channel, is arranged between the cylinder housing (1) and the inner cylinder (2) at the end where the key is first inserted, in that said guiding element (14) is supported by said profile disc (15) and in that the shape of the key opening (32) of the profile disc (15) is selectable so as to define one of a range of different shapes, thereby providing one of a range of possible different lock-key-families based on different profiles of key shafts. A combination according to claim 7, characterised in that said guiding element (14) is supported by a lifting O-locking disc (3), arranged along the key channel towards the inner part of the inner cylinder (2) and that the key opening (6) of said lifting O-locking disc (3) is arranged to be varied independently of said profile disc (15) for further defining the profile of the key shaft at its end first inserted in the lock. A key or a key blank for use in operating a disc cylinder lock-key-combination according to any one of the preceding claims, wherein the shaft part (12) thereof has an at least substantially rectangular cross-section and comprises at least one groove (25), formed in one of the wider side planes of the rectangular cross-section, extending lengthwise over the shaft and capable of accommodating in use a guiding element (14) of a corresponding lock-key-combination, and wherein the shaft part (12) comprises a first corner (26) and in association therewith one of the wider side planes (33) of the rectangular cross-section, starting from which the combination surfaces (27) determining the opening combination of a given lock are cut or arranged to be cut as bevelled surfaces to be spaced at selected intervals from each other, each bevelled surface extending from one of the wider side planes towards a second corner (28) of the rectangular cross-section, said second corner (28) being located adjacent to the said first corner (26) and associated with the other of the wider side planes of the rectangular cross-section, characterised in that the key blank profile portion of said second corner (28) is substantially rounded. A key according to claim 9, characterised in that it comprises two series of combination surfaces (27) located symmetrically on opposite sides of the centre axis of the shaft part of the key (12), and that the edges (28) of the shaft part of the key (12) located adjacent to said series of combination surfaces (27) are rounded. A disc cylinder-key-combination comprising a stack of locking discs (3, 4) aligned to define a key channel (6, 7) and independently turnable by a key (12) inserted in the channel from rest positions which define a locked condition of the lock into respective angular lock-open positions which define an open condition of the lock and at least one key-engaging member (14) captive in, and extending axially of, the key channel, the key (12) having combination surfaces (27) for separately moving discs (3, 4) into their respective lock-open positions and a groove (25) for engaging with the key-engaging member (14) during insertion of the key into the lock, characterised in that the key-engaging member (14) is designed to interengage with at least some of the discs (4) to return them to their rest positions as the key (12) returns the lock to its locked condition.

Inventors: NEVALAINEN KYOSTI, RAMO SEIJA, VEHVILAINEN PEKKA, NEVALAINEN, KYOSTI, RAMO, SEIJA, VEHVILAINEN, PEKKA
Applicants: ABLOY SECURITY LTD OY, ABLOY SECURITY LTD. OY
Application year: 1994
Main classification: E05B21
IPC codes: E05B29, E05B21